Preparation and properties of microcrystalline cellulose-thermoplastic polyurethane core-shell structured aerogel fibres

To enhance the mechanical strength and thermal insulation properties of aerogel fibers, microcrystalline cellulose(MCC) and thermoplastic polyurethane(TPU) are employed in coaxial wet spinning. Through solvent exchange and freeze-drying, aerogel fibers with a porous MCC aerogel core layer enveloped by a TPU shell layer are prepared. The morphology, chemical crystalline structure, thermal stability, mechanical properties, and thermal insulation performance of the MCC-TPU aerogel fibers(MTAFs) are systematically analyzed and evaluated. The results demonstrate that upon dissolution and regeneration into MCC aerogel fibers, the crystalline structure of MCC transitio ns from cellulose Ⅰ to cellulose Ⅱ. The MTAFs exhibit a hierarchical porous structure comprising both mesopores and micropores, with a density of 0.169 g/cm~3, a specific surface area of 6.460 m~2/g, and an average pore diameter of 17.005 nm. When the mass fraction of MCC is 1.5% and that of TPU is 25%, the MTAFs exhibit optimal tensile properties, with a tensile strength of 2.32 MPa and an elongation at break of 567.47%. These values represent an increase of 246% and 11 027%, respectively, compared to MTAFs with an MCC mass fraction of 3.0% and a TPU mass fraction of 0%. These fibers can be woven into textiles, showcasing excellent mechanical properties and flexibility. The incorporation of TPU enhances the overall thermal stability of the aerogel fibers. The MTAFs achieve a maximum temperature differential of up to 22.48 ℃ with the heating stage, exhibit an overall infrared emissivity below0.5, and effectively reduce thermal radiation. These attributes make them highly promising for applications in high-performance thermal insulation textiles.